1. Field
The subject invention is in the field of caps for containers for liquids, particularly caps for bottles which contain drinkable liquids and which are inverted when being installed on and removed from dispensers specifically designed to accommodate such containers. A typical and preferred container has a neck which, when the container is inverted fits into an opening in the top of the dispenser. A capped tube, known as a probe or liquid supply tube is part of the dispenser and, when a container is installed in the dispenser, extends upward into the neck of the container. Caps are commercially available for use on the necks of such containers to limit leakage while the container is being installed on and removed from the dispenser. Such caps have an outer cylindrical portion, which fits snugly over the neck and holds the cap in place and an inner cylindrical portion which engages the probe. The free end of the inner cylindrical portion is made closed, is opened as the probe passes through the inner cylindrical portion and closes again when the probe is removed from the inner cylindrical portion when the container is removed from the dispenser. The subject invention is an improved configuration of the opening/closing end of the inner cylinder of the type of cap described.
2. Prior Art
There are two basic types of caps made for the purpose described above: two part caps as typified by the cap described in U.S. Pat. No. 5,392,939, Hidding et al and one part caps as typified by the cap described in U.S. Pat. No. 5,687,867, Lamoureux. The subject cap is a one-piece cap and the Lamoureux patent is the closest known prior art to the subject invention. The free end of the inner cylinder of the Lamoureux cap is conical and frangible and projects out of the inner cylinder, termed the guiding portion in that patent. The Lamoureux end projects in the direction in which the probe moves through it when a container is installed on a dispenser. Experience has shown that the Lamoureux cap does not close as consistently and reliably as desired and allows tolerable but undesired leakage when a container still containing some liquid is removed from a dispenser. Accordingly, the primary objective of the subject invention is to provide, for containers used on drinking water dispensers, a cap having improved sealing capability when the container is removed from a dispenser.